write a go solution for Description:
Harry Potter is hiking in the Alps surrounding Lake Geneva. In this area there are m cabins, numbered 1 to m. Each cabin is connected, with one or more trails, to a central meeting point next to the lake. Each trail is either short or long. Cabin i is connected with s_i short trails and l_i long trails to the lake.

Each day, Harry walks a trail from the cabin where he currently is to Lake Geneva, and then from there he walks a trail to any of the m cabins (including the one he started in). However, as he has to finish the hike in a day, at least one of the two trails has to be short.

How many possible combinations of trails can Harry take if he starts in cabin 1 and walks for n days?

Give the answer modulo 10^9+7.

Input Format:
The first line contains the integers m and n.

The second line contains m integers, s_1,...,s_m, where s_i is the number of short trails between cabin i and Lake Geneva.

The third and last line contains m integers, l_1,...,l_m, where l_i is the number of long trails between cabin i and Lake Geneva.

We have the following constraints:

0<=s_i,l_i<=10^3.

1<=m<=10^2.

1<=n<=10^3.

Output Format:
The number of possible combinations of trails, modulo 10^9+7.

Note:
None. Output only the code with no comments, explanation, or additional text.